SUPPORT DEVICE FOR PIVOTAL MEMBER OF KEYBOARD INSTRUMENT AND METHOD OF MANUFACTURING THE SAME

Abstract

A support device for a pivotal member of a keyboard instrument, in which opposite ends of a pivotal pin fixed to a pivotal member can be each properly positioned in the center of a pin hole, to thereby enable the pivotal member to perform efficient and stable pivotal motion. The support device that pivotally supports the pivotal member pivotally moved by key depression includes a flange body including two support walls opposed to each other with a predetermined spacing therebetween, and two pin holes which are formed in the respective support walls and in which opposite ends of the pivotal pin are inserted, respectively, and two bearings fixed in the pin holes in an inserted state and having opposite ends of the pivotal pin inserted therein, for pivotally supporting the pivotal. Each bearing is formed by a braid formed in a hollow cylindrical shape.

Claims

1. A support device for a pivotal member of a keyboard instrument, which pivotally supports the pivotal member pivotally moved by key depression, via a pivotal pin fixed to the pivotal member, comprising: a support device body including two support walls opposed to each other with a predetermined spacing therebetween, and two pin holes which are formed in the respective support walls and in which opposite ends of the pivotal pin are inserted, respectively; and two bearings which are fixed in the respective pin holes in a state inserted therein and have the opposite ends of the pivotal pin inserted therein, the two bearings pivotally supporting the pivotal pin, wherein each of the two bearings is formed by a braid formed in a hollow cylindrical shape.

2. The support device according to claim 1, wherein the braid is formed of fluorine fibers.

3. A method of manufacturing a support device for a pivotal member of a keyboard instrument, which pivotally supports the pivotal member pivotally moved by key depression, via a pivotal pin fixed to the pivotal member, the method comprising: a core material-containing braid-preparing step of preparing a core material-containing braid formed by a slender elongated core material and a braid extending along a length of the core material and covering a peripheral surface of the core material; a support device body-preparing step of preparing a support device body including two support walls opposed to each other with a predetermined spacing therebetween, and two pin holes which are formed in the respective support walls and in which opposite ends of the pivotal pin are inserted, respectively; a core material-containing braid-inserting and fixing step of inserting the prepared core material-containing braid through the two pin holes of the support device body and fixing the core material-containing braid to the support device body; a core material-containing braid-cutting step or cutting the core material-containing braid inserted through the two pin holes, along inner and outer surfaces of each of the support walls such that cut surfaces of the core material-containing braid become flush with the respective inner and outer surface; and a pivotal pin-mounting step of mounting the pivotal member between the two support walls of the support device body such that a hole portion of the pivotal member, through which the pivotal pin is to be inserted, and the pin holes of the two support walls are aligned in a straight line, and inserting the pivotal pin from outside one of the two support walls into the pin hole of the one of the two support walls, the hole portion of the pivotal member, and the pin hole of the other of the two support walls to thereby mount the pivotal pin while pushing out the core material of the core material-containing braid from each pin hole.

4. The method according to claim 3, wherein the pivotal member includes a plurality of kinds of pivotal members, wherein in the core material-containing braid-preparing step, a core material-containing braid in which the core material and the braid have respective predetermined diameters is prepared, and wherein in the support device body-preparing step, the support device body has a diameter of the pin holes set according to a kind of the pivotal member to be supported thereby.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a side view of an action of an upright piano to which is applied a support device for a pivotal member, according to an embodiment of the present invention, and components around the action.

[0019] FIG. 2 is an exploded perspective view of a hammer assembly, a butt flange, etc. appearing in FIG. 1.

[0020] FIG. 3 is an exploded perspective view of a wippen, a jack, a wippen flange, etc. appearing in FIG. 1.

[0021] FIGS. 4A to 4C are views useful in explaining a method of manufacturing a flange, in which FIG. 4A is a perspective view of a core material-containing braid, FIG. 4B is a cross-sectional view of the core material-containing braid cut at right angles to the longitudinal direction thereof, and FIG. 4C is a perspective view of a flange body.

[0022] FIGS. 5A to 5C are views useful in explaining the method of manufacturing the flange, in which FIG. 5A is a perspective view showing a state in which the core material-containing braid has been inserted through respective pin holes of two support walls of the flange body, FIG. 5B is a perspective view showing a state in which the core material-containing braid inserted through the pin holes has been cut along the outer and inner surfaces of each of the support walls, and FIG. 5C is a cross-sectional view of the two support walls of the flange body in FIG. 5B.

[0023] FIGS. 6A to 6C are views useful in explaining the method of manufacturing the flange, in which FIG. 6A shows a state before mounting a pivotal member to the flange, FIG. 6B shows a state in which the pivotal member has been mounted between the two support walls of the flange, and FIG. 6C shows a state in which a center pin has been mounted in the flange and the pivotal member.

[0024] FIGS. 7A and 7B are perspective views of a conventional flange, in which FIG. 7A shows a state in which bushing cloths and a pivotal pin have been mounted, and FIG. 7B shows a state in which the bushing cloths and the pivotal pin have been removed.

[0025] FIGS. 8A to 8D are views useful in explaining a procedure in which the bushing cloths are mounted in the flange.

[0026] FIGS. 9A to 9C are enlarged views of the bushing cloth mounted in a pin hole, in which FIG. 9A shows a state in which the bushing cloth has been properly mounted, FIG. 9B shows a state in which a gap has been formed at a joint of the bushing cloth, and FIG. 9C shows a state in which joint-forming ends of the bushing cloth have overlapped.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] The present invention will now be described in detail with reference to the drawings showing a preferred embodiment thereof. FIG. 1 shows an action of an upright piano to which is applied a pivotal member support device according to an embodiment of the present invention, and components around the action. More specifically, FIG. 1 shows the action, denoted by reference numeral 1, a keyboard 2, a hammer assembly (pivotal member) including a hammer 3, etc. in a key-released state. In the following description, a near side and a far side of the upright piano as viewed from a player (a right side and a left side as viewed in FIG. 1) will be referred to as “front” and “rear”, respectively.

[0028] The keyboard 2 is comprised of a plurality of keys 2a (only one of which is shown in FIG. 1) arranged side by side in a left-right direction of the upright piano. Each of the keys 2a extends in a front-rear direction (left-right direction as viewed in FIG. 1), and is supported in a manner pivotally movable about a balance pin 5a erected on a keyframe 5 on a keybed 10.

[0029] On each of left and right ends of the keybed 10, there is provided an action bracket (not shown), and the action 1 is disposed above the rear end of the keyboard 2 between the two action brackets. The action 1 includes a wippen 21 (pivotal member), a jack 22 (pivotal member), and a butt 23, and these components are provided in association with each key 2a. Further, as shown in FIG. 2, a hammer 3 comprised of a hammer shank 3a extending upward over a predetermined length and a hammer head 3b provided on the upper end of the hammer shank 3a is attached to the butt 23, and the hammer assembly 4 is formed by the butt 23, the hammer 3, and so forth.

[0030] Between the left and right action brackets, there are provided a center rail 6, a hammer rail 7, and so forth, in a manner extending in the left-right direction (depth direction as viewed in FIG. 1). A butt flange 11 for pivotally supporting the hammer assembly 4 via the butt 23 is fastened by a butt flange screw 12c (see FIG. 2) to the upper end of the front surface of the center rail 6, and is provided in association with each key 2a.

[0031] Each of the butt flanges 11 is comprised of a flange body 12 (support device body) and two bearings 13 mounted in two pin holes 12b, referred to hereinafter, of the flange body 12, respectively. The flange body 12 is made of a synthetic resin, and has an upper portion thereof bifurcated into two left and right support walls 12a and 12a. The two support walls 12a and 12a are opposed to each other with a predetermined spacing therebetween, and the pin holes 12b having a predetermined diameter are formed in the respective support walls 12a in a manner each extending through the associated support wall 12a.

[0032] Each of the bearings 13 is formed into a hollow cylindrical shape having substantially the same outer diameter as the diameter of the pin hole 12b and substantially the same inner diameter as the diameter of a center pin 14, referred to hereinafter. The bearing 13 is formed by a braid made of fluorine fibers.

[0033] In the butt flange 11 constructed as above, the single center pin 14 (pivotal pin) having a predetermined length is mounted to the left and right support walls 12a and 12a, in a state in which the center pin 14 is inserted in the left and right pin holes 12b and 12b having the respective two bearings 13 and 13 mounted therein. Further, a portion of the center pin 14 between the left and right support walls 12a and 12a is fixed by a butt plate screw 23b in a state sandwiched between the front lower end of the butt 23 of the hammer assembly 4 and a butt plate 23a, whereby the center pin 14 is integrally assembled to the butt 23. With the construction described above, the hammer assembly 4 is pivotally supported by the butt flange 11 via the center pin 14 and the left and right bearings 13 and 13.

[0034] As shown in FIG. 1, the wippen 21 is made of a synthetic resin and formed into a predetermined shape. Specifically, the wippen 21 has a heel portion 21a protruding downward, and is placed on a capstan button 2b provided on the rear end of the associated key 2a via the heel portion 21a. Further, the wippen 21 has its rear end supported by a wippen flange 15.

[0035] As shown in FIG. 3, the wippen flange 15 is constructed similar to the aforementioned butt flange 11. More specifically, the wippen flange 15 is comprised of a flange body 16 (support device body) made of a synthetic resin and two bearings 13 and 13, and the bearings 13 and 13 are mounted in pin holes 16b and 16b of respective two support walls 16a and 16a of the flange body 16. The wippen flange 15 is fastened to the lower end of the rear surface of the center rail 6 by a wippen flange screw 16c, in a state in which the two support walls 16a and 16a extend downward.

[0036] The wippen 21 has a rear portion thereof formed with a pin mounting hole 21b (hole portion) extending therethrough in the left-right direction, and the wippen 21 and the wippen flange 15 are assembled to each other in a state in which the pin mounting hole 21b is positioned between the left and right support walls 16a and 16a of the wippen flange 15. In this state, the single center pin 14 is inserted through the left and right pin holes 16b and 16b, and the pin mounting hole 21b therebetween. The center pin 14 is integrally assembled to the wippen 21, and the wippen 21 is pivotally supported by the wippen flange 15 via the center pin 14 and the left and right bearings 13 and 13.

[0037] Further, at a location close to the center of the wippen 21 in the front-rear direction, a flange part 17 protruding upward is integrally formed with the wippen 21. Similar to the butt flange 11 and the wippen flange 15, the flange part 17 includes left and right support walls 17a and 17a formed into a bifurcated shape and each formed with a pin hole 17b, and bearings 13 and 13 mounted in the respective pin holes 17b. The jack 22 is assembled to the flange part 17.

[0038] The jack 22 is made of a synthetic resin and formed into an L shape in side view by a root portion 22a extending in the front-rear direction and a hammer push-up part 22b extending upward from a rear end of the root portion 22a. In a corner of the jack 22 formed by the root portion 22a and the hammer push-up part 22b, there is formed a pin mounting hole 22c (hole portion) extending therethrough in the left-right direction, and the wippen 21 and the jack 22 are assembled to each other in a state in which the pin mounting hole 22c is positioned between the left and right support walls 17a and 17a of the flange part 17. In this state, the single center pin 14 is inserted through the left and right pin holes 17b and 17b, and the pin mounting hole 22c therebetween. The center pin 14 is integrally assembled to the jack 22, and the jack 22 is pivotally supported by the flange part 17 via the center pin 14 and the left and right bearings 13 and 13.

[0039] Further, as shown in FIG. 1, the center rail 6 is provided with a plurality of regulating brackets 8a (only one of which is shown) each extending forward and a regulating rail 8b attached to the front ends of the regulating brackets 8a and extending in the left-right direction. Attached to the bottom of the regulating rail 8b are a plurality of regulating buttons 8c (only one of which is shown) in association with the respective keys 2a. Further, on the rear end of the wippen 21, there is erected a spoon 24 for driving a damper 25, described hereinafter.

[0040] Furthermore, as shown in FIG. 1, a damper flange 18 is attached to the top surface of the center rail 6. The damper flange 18 is constructed similar to the butt flange 11 and the wippen flange 15. More specifically, the damper flange 18 is comprised of a flange body 19 (support device body) made of a synthetic resin and two bearings 13 and 13 (only one of which is shown), and the bearings 13 and 13 are mounted in pin holes 19b and 19b of respective two support walls 19a and 19a (only one of which is shown) of the flange body 19. The damper flange 18 is screwed to the center rail 6, in a state in which the two support walls 19a and 19a extend rearward.

[0041] The damper 25 is attached to the damper flange 18. The damper 25 includes a vertically extending damper lever 25a, a damper wire 25b extending upward from the upper end of the damper lever 25a, and a damper head 25c attached to the upper end of the damper wire 25b. The damper 25 is pivotally supported by the damper flange 18 via a center pin 14 inserted through a pin hole (not shown) formed at a vertical center of the damper lever 25a, and the pin holes 19b and 19b of the respective left and right support walls 19a and 19a of the flange body 19. The damper head 25c is urged rearward by a damper lever spring 25d, and is in contact, from the front side, with a string S stretched in a vertically extending manner, when in a key-released state.

[0042] Now, a description will be given of sequential operations performed in the above-described upright piano between the start of key depression and the end of the key depression. First, as the key 2a is depressed by the player in the key-released state shown in FIG. 1, the key 2a pivotally moves about the balance pin 5a in the clockwise direction as viewed in FIG. 1, and the wippen 21 placed on the rear end of the key 2a is pushed up by the key 2a, whereby the wippen 21 is pivotally moved upward (counterclockwise, as viewed in FIG. 1) about the center pin 14 of the wippen flange 15. In accordance with this pivotal motion of the wippen 21, the lower end of the damper lever 25a is pressed rearward by the spoon 24, whereby the damper 25 pivotally moves clockwise about the center pin 14 of the damper flange 18. This moves the damper head 25c away from the string S.

[0043] Further, in accordance with the pivotal motion of the wippen 21 described above, the jack 22 moves upward together with the wippen 21, while the hammer 3 is pushed up by the hammer push-up part 22b of the jack 22 via the butt 23 and is thereby pivotally moved counterclockwise about the center pin 14 of the butt flange 11 toward the string S located rearward of the hammer 3.

[0044] When the key 2a is further pivotally moved by being depressed, the root portion 22a of the jack 22 is brought into abutment with the regulating button 8c from below. As a consequence, further upward motion of the jack 22 is blocked, and the jack 22 pivotally moves about the center pin 14 of the flange part 17 in the clockwise direction with respect to the wippen 21.

[0045] Then, when the key 2a further pivotally moves, the hammer push-up part 22b of the jack 22 comes forward off the butt 23, whereby the jack 22 is disengaged from the hammer assembly 4. Even after disengagement of the jack 22, the hammer 3 is pivotally moved by inertia, and the hammer head 3h collides with the string S and vibrates the same, whereby a piano tone is generated. Thereafter, a repellent force of the string S causes the hammer assembly 4 to perform pivotal return motion in the clockwise direction about the center pin 14 of the butt flange 11.

[0046] When the key depression is completed to release the key 2a, the key 2a is pivotally moved about the balance pin 5a to return to its key-released state prior to key depression. At this time, the wippen 21, the jack 22, and the damper 25 of the action 1 each also perform pivotal return motion in an opposite direction to the direction during key depression and return to a key-released state prior before key depression.

[0047] Next, a description will be given, with reference to FIGS. 4A to 6C, of a method of manufacturing the butt flange 11, the wippen flange 15, the flange part 17 and the damper flange 18 that pivotally support the hammer assembly 4, the wippen 21, the jack 22, and the damper 25, respectively. In the following description, the hammer assembly 4, the wippen 21, the jack 22, and the damper 25 are generically referred to as “the pivotal member”, and the butt flange 11, the wippen flange 15, the flange part 17 and the damper flange 18 are generically referred to as “the flange”.

[0048] First, a predetermined core material-containing braid for forming bearings of the flange is prepared, and a flange body is also prepared. FIGS. 4A and 4B show the core material-containing braid. This core material-containing braid 31 is comprised of a slender elongated core material 31a and a braid 31b extending along the length of the core material 31a and covering the peripheral surface of the same. The core material 31a is made of a synthetic resin and has a predetermined diameter D (e.g. 1 mm), while the braid 31b has a predetermined outer diameter W (e.g. 2 mm) and is made of fluorine fibers. Note that the core material-containing braid 31 is formed by knitting a large number of fluorine fibers such that the fluorine fibers obliquely cross each other along the length of the core material 31a prepared in advance. This forms the braid 31b itself into a hollow cylindrical shape having a hollow extending over the whole length thereof.

[0049] The flange body 33 shown in FIG. 4C has two left and right support walls 33a and 33a opposed to each other with a predetermined spacing therebetween, and each of the support walls 33a has a pin hole 33b extending therethrough and having a predetermined diameter (e.g. 2 mm).

[0050] After the core material-containing braid 31 and the flange body 33 constructed as above are prepared, first, the core material-containing braid 31 is inserted through the two pin holes 33b and 33b of the flange body 33 as shown in FIG. 5A. Note that prior to this, an adhesive is applied in advance to predetermined portions of the surface of the core material-containing braid 31 and/or the inner peripheral surface of each of the pin holes 33b and 33b of the flange body 33. This causes the core material-containing braid 31 to be fixed to the pin holes 33b and 33b via portions thereof in contact with the inner peripheral surfaces of the pin holes 33b and 33b.

[0051] Next, the core material-containing braid 31 is cut by a cutter, not shown, along the outer and inner surfaces of each of the support walls 33a such that the cut surfaces thereof become flush with the respective outer and inner surfaces of each of the support walls 33a. This mounts the core material-containing braid 31 in each of the two pin holes 33b and 33b of the flange body 33 in a state filling the associated pin hole 33b, as shown in FIGS. 5B and 5C. More specifically, the core material-containing braid 31 is mounted in each of the pin holes 33h, in a state in which the core material 31a is positioned in the central portion of the associated pin hole 33h, and the braid 31b is positioned outside the core material 31a and bonded to the inner peripheral surface of the associated pin hole 33h.

[0052] FIGS. 6A to 6C show a procedure in which a pivotal member 30 and a flange 32 are coupled to each other. Note that as shown in FIG. 6A, the pivotal member 30 is formed therethrough with a pin mounting hole 30a (hole portion) for mounting the center pin 14 in a state inserted through the pivotal member 30.

[0053] First, as shown in FIG. 6B, the pivotal member 30 is mounted between the two support walls 33a and 33a such that the pin mounting hole 30a of the pivotal member 30 and the two pin holes 33h and 33h of the flange 32 are aligned in a straight line. Then, the center pin 14 is inserted from outside one of the support walls 33a into the center of the associated pin hole 33b. In doing this, the center pin 14 is inserted, as shown in FIG. 6C, such that the center pin 14 extends through the two support walls 33h and 33h of the flange 32 and the pivotal member 30, while pushing out the core material 31a of the core material-containing braid 31 mounted in each of the two pin holes 33b and 33b. This causes the center pin 14 to be fixed in a state inserted through the pin mounting hole 30a of the pivotal member 30, and the opposite ends of the center pin 14 are pivotally supported by the two support walls 33a and 33a, respectively, via the respective braids 31b and 31b as bearings.

[0054] As described above in detail, according to the present embodiment, the opposite ends of the center pin 14 fixed to the pivotal member 30, such as the hammer assembly 4, the wippen 21, the jack 22, and the damper 25, are pivotally supported by the associated flange 32 via the respective bearings 13 and 13. Each of the bearings 13 is formed by a cylindrical braid having hollow therein, and therefore, differently from the related art in which a strip-shaped cloth is rolled up into a bushing cloth, it is possible to position each of the opposite ends of the center pin 14 properly in the center of the associated pin hole 33b of the flange 32 and cause the pivotal member 30 to perform efficient and stable pivotal motion. Further, the bearings 13 are formed using the core material-containing braid 31, and the pivotal member 30 and the flange 32 are coupled by the center pin 14 as described hereinabove, and hence it is possible to easily obtain the flange 32 which enables the pivotal member 30 to perform efficient and stable pivotal motion.

[0055] It is preferable that the diameter of a pin hole 33b that is formed in a flange 32 is set according to the kind of a pivotal member 30 to be supported by the flange 32. For example, when a flange 32 (flange body 33) is to support a pivotal member 30 (e.g. the jack 22) which should have a higher degree of rotatability, the diameter of the pin hole 33b in the flange 32 is increased to thereby reduce friction of the bearing 13 (braid 31b), which acts on the center pin 14, whereby the degree of rotatability of the pivotal member 30 can be made higher. On the other hand, when a flange 32 is to support a pivotal member 30 (e.g. the wippen 21) which should have a lower degree of rotatability, the diameter of the pin hole 33b in the flange 32 is reduced to thereby increase friction of the bearing 13 (braid 31b), which acts on the center pin 14, whereby the degree of rotatability of the pivotal member 30 can be made lower. Therefore, even in a case where a core material-containing braid 31 of a single type is used, it is possible to provide a flange 32 suitable for a degree of rotatability demanded of a pivotal member 30.

[0056] Note that the present invention is not limited to the above-described embodiment, but can be practiced in various forms. For example, although in the above-described embodiment, the support device of the present invention is applied to the flanges of an upright piano, the present invention is not limited to this, but it may be applied e.g. Togo flanges for pivotally supporting various pivotal members of a grand piano or any other keyboard instrument, such as an electronic piano.

[0057] Further, although the braid 31b is made of fluorine fibers, by way of example, this is not limitative, but it is possible to adopt other various materials. Furthermore, the detailed construction of each of the action 1 and the various flanges 11, 15, 17, and 18 is described only by way of example, and therefore these can be changed, as desired, within the scope of the subject matter of the present invention.